Fouling resistance of novel amphiphilic polyampholyte membranes with varying hydrophobicity towards common foulants and cell culture media

•Amphiphilic polyampholyte membranes are extremely fouling resistant.•Pore size of membranes is independent of hydrophobic content.•Cell culture media did not foul amphiphilic polyampholyte membrane.•High hydrophobic content membranes are still highly fouling resistant. Self-assembly is a spontaneous and scalable manufacturing method to create much-needed fouling resistant membranes with narrow pore size distributions. However, there is a limited number of self-assembled membrane chemistries that can access pore sizes below 2 nm. Novel thin film composite membranes with a selective layer manufactured from a random Polyampholyte Amphiphilic Copolymer (r-PAC) have an effective pore size of 1.5 nm, relevant to various nanofiltration and water treatment applications. This is the first study that reports the membrane performance of novel r-PAC layers, prepared with varying degrees of ionic content, in filtering several classes of foulants (oil, organics, proteins, and complex mixtures). The net neutral charge of the r-PACs used enabled steady salt rejections independent of the ionic strength of the feed. The best performing r-PAC membrane composition showed no irreversible flux decline in all fouling tests and was further tested with a realistic feed, a complex cell culture media mixture utilized in cellular agriculture. This membrane exhibited an impressive 0 % irreversible flux decline after filtering the cell culture media for 20 h while a comparable commercial membrane exhibited 90 % irreversible flux decline. The chemical stability and excellent fouling resistance behavior of these membrane materials to a broad range of feeds implies these materials can enable the filtration of feeds with extreme fouling potential in biomanufacturing, wastewater treatment, and resource recovery applications.